In trying to solve this mystery we should keep in mind the life history of
the chambered nautilus. It was my understanding that nautiluses are free
swimming, at rather extreme depths most of the time. In photos of living
specimens I have never seen any "growths" or parasites on the shell.

Predation by crabs or boring mollusks or starfish seems unlikely in an
animal that never comes in contact with the ocean bottom. Octopuses remain
mostly near the bottom and unlikely to be able to get to nautiluses on a
regular bases.

Also, the nautilus does not have an operculum.  the soft parts are rather
easily accessible so why would an animal bother to bore through the shell if
it didn't need to?

Predation by sharks or other large fish is a possibility I guess and perhaps
the punctures are caused by the fish grabbing the soft parts and
accidentally poking the shell at the same time. Squid are large and
carniverous and might make a meal of a nautilus but I don't know how or why
they would cause bored holes.

Is there a possibility that the holes are bored from the inside?  Perhaps an
internal parasite needing a breathing hole?

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------